Field of the Invention
The present invention pertains to the art of cooking appliances and, more particularly, to a convection cooking system for an appliance having a small oven cavity.
Description of the Related Art
Conventional cooking appliances generally perform cooking operations through radiant heating developed from bake and/or broil elements. Such types of cooking appliances can take various forms, mainly ranges and wall ovens. While conventional or radiant heat cooking is suitable to a wide assortment of food types, the overall cooking process, especially baking, can be quite slow. The pre-heat time, combined with the cook time, is longer than most consumers desire.
Some radiant cooking appliances incorporate internal fans which can be used during certain cooking operations in order to generate an air flow within an oven cavity to enhance even cooking. Forced air convection allows for cooking at lower temperatures as compared to conventional radiant cooking processes. In addition, the forced air streams serve to disrupt a thermal insulation layer about the food item which increases the heat transfer rate between the food item and its surroundings, thereby reducing required cooking times.
In convection cooking appliances, the air flow can be designed to recirculate within the oven cavity, flow through the oven cavity and be exhausted, or a combination of both of these configurations. For obvious reasons, it is desirable to enhance the efficiency of any air flow system in order to reduce associated operating costs and minimize the required fan size, while still producing an effective air flow pattern and rate. Most convection systems employ a fan which draws cooking cavity air into a central intake portion and directs the air radially outward across a heating unit for re-introduction back into the oven cavity through plural, spaced exhaust outlets. Most often, the outlets are arranged either directly adjacent the side walls of the cooking cavity or the outlets are simply arranged in a generally circular configuration about the air inlet and angled toward the side walls. In either case, the air is exhausted along the side walls, flows forward towards a door for the oven cavity and then is re-directed into a central oven cavity region back to the fan intake.
With relatively large oven cavities, such as oven cavities of 4.0 cubic feet or more, the above-described air flow arrangement is quite effective. However, with smaller oven cavities in the order of 2.5 cubic feet or less, special spatial and air flow considerations are encountered. For instance, from just a dimensional standpoint, utilizing a conventional convection arrangement in a small oven cavity would result in the inlet and outlet portions being in close proximity which would tend to reduce the amount of air turnover inside the oven cavity. Therefore, regardless of the existence of numerous convection systems in the art, there exists a need for an enhanced convection air flow system for use in a cooking appliance, particularly a cooking appliance having a small oven cavity.